Field of the Invention
The present invention relates to a car-charging system of a car equipped with a charge-accumulating device chargeable from the outside thereof, and particularly to authentication of the car.
Description of the Related Art
In recent years, an electric car equipped with a charge-accumulating device and an electric motor, and a so-called hybrid car have been studied as environmentally friendly vehicles. Such cars are driven by an electric motor using electric power of a charge-accumulating device as they run, and therefore it is required to charge the charge-accumulating device. To charge the charge-accumulating device, a dedicated power source in a public parking area and a commercial household power source can be used.
When charging the charge-accumulating device, it is necessary to perform authentication between a power-supplying device and car in question regardless of whether the car is in a public parking area or at home and check whether or not the car is one which may be charged for the purpose of preventing the theft of electric power.
A prior art-related patent document, Japanese Unexamined Patent Application Publication JP-A-2007-228695 discloses a car-charging system which uses information on an ETC card to authenticate a user of the car. Also, another document, JP-A-2008-61432 discloses a car-charging system which uses a cryptographic key recorded in a charger of a car for authentication.
Further, according to a prior art-related non-patent document, ITS Shyasai-ki DSRC-bu hyou-jun shiyou (ITS onboard device DSRC part standard specifications) JEITA TT-6002A, a DSRC onboard device, which is a DSRC application system, has been standardized and put to practical use as a communication system such that a road-side unit and a car authenticate each other and exchange information therebetween. Likewise, another non-patent document, dedicated short range communication (hereinafter referred to as “DSRC”) basic application interface specifications' guideline ITS FORUM RC-004 standardizes and shows an application software program for a road-side unit to authenticate an onboard device and to bill a car concerned.
It is preferable that car-charging systems use a common car-authentication method in both cases where charging is performed from a dedicated power source in a public parking area and where charging is conducted from a commercial household power source.
However, the car-charging system as disclosed by the patent document JP-A-2007-228695 has the problem of the impossibility of supporting a power-supplying device for household use. This is because such car-charging system needs to use ETC card information to identify an individual in authentication although the information is undisclosed in general. Further, the car-charging system as disclosed by the patent document JP-A-2008-61432, which uses a cryptographic key recorded in a car-charging device in authentication, has the problem that as the cryptographic key varies depending on the car manufacturer and the type or model of the car, it has no general versatility and cannot be used in e.g. a public parking area.
With a functional configuration of a DSRC onboard device defined by ITS Shyasai-ki DSRC-bu hyou-jun shiyou (ITS onboard device DSRC part standard specifications) JEITA TT-6002A, an application software program can be executed through the wireless communication, but it is not taken into account to allow an external device to execute it through an interface.